THE U. S. Regional Poultry Research Laboratory has as its objective the improvement of viability in poultry. In formulating the research program of the laboratory it was determined that the avian-leukosis complex, of which fowl paralysis is a common manifestation, constitutes the most hazardous disease problem confronting the poultry industry. After due delibertaion a coördinated program of research in genetics, pathology, nutrition, and management was recommended as the most likely means of determining the cause of the disease complex, its method of transmission, and the development of measures for its control. In developing studies of the avian-leukosis complex it was suggested, in so far as the major objectives of this research can be attained without sacrifice, that desirable utility qualities of the poultry be maintained and improved in the breeding aspects of the research conducted at the laboratory.Although the primary objective of the Regional Poultry Research Laboratory program is .